[Jetsnack] Add preview placeholder to images (android#453)

Use CoilImage's new previewPlaceholder to display a placeholder when in preview mode

Author: chrisbanes

Jetsnack/app/src/main/java/com/example/jetsnack/ui/components/Snacks.kt

@@ -51,6 +51,7 @@ import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
+import com.example.jetsnack.R
 import com.example.jetsnack.model.CollectionType
 import com.example.jetsnack.model.Snack
 import com.example.jetsnack.model.SnackCollection
@@ -281,6 +282,7 @@ fun SnackImage(
         CoilImage(
             data = imageUrl,
             contentDescription = contentDescription,
+            previewPlaceholder = R.drawable.placeholder,
             contentScale = ContentScale.Crop,
             modifier = Modifier.fillMaxSize()
         )

Jetsnack/app/src/main/res/drawable-nodpi/placeholder.jpg

@@ -40,6 +40,8 @@ subprojects {
 
         if (!Libs.AndroidX.Compose.snapshot.isEmpty()) {
             maven { url "https://androidx.dev/snapshots/builds/${Libs.AndroidX.Compose.snapshot}/artifacts/repository/" }
+        }
+        if (Libs.Accompanist.version.endsWith("SNAPSHOT")) {
             maven { url 'https://oss.sonatype.org/content/repositories/snapshots/' }
         }
     }

Jetsnack/build.gradle

@@ -24,7 +24,7 @@ object Libs {
     const val androidGradlePlugin = "com.android.tools.build:gradle:7.0.0-alpha11"
 
     object Accompanist {
-        private const val version = "0.7.0"
+        const val version = "0.7.1-SNAPSHOT"
         const val coil = "com.google.accompanist:accompanist-coil:$version"
         const val insets = "com.google.accompanist:accompanist-insets:$version"
     }